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Enthalpy· The heat (energy) content of a system· Enthalpy change (H); the heat energy change measured under conditions of constant pressure· H = Hp ­ Hr· Subtracting the total enthalpy of the reactants from the total enthalpy of the products…read more

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Standard conditions· Value of enthalpy change is dependant on..· The temperature and pressure· The amount of substance used· The value, in KJ, is always given per mole of substance…read more

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Enthalpy of formation/combustion· Enthalpy of formation; the enthalpy change when one mole of a compound is formed from its elements in their standard states· By definition, the standard enthalpy of formation of an element in its standard state is zero· Enthalpy of combustion; the enthalpy change when one mole of a substance is burned completely in oxygen under standard conditions…read more

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Calculating enthalpy change· Enthalpy changes are measured using a calorimeter, which insulates the reaction system from its surroundings· q=mcT· Specific heat capacity; the heat energy required to raise the temperature of 1g of a substance by 1K· For pure water, the specific heat capacity (c) is 4.18…read more